Motorists on their Wednesday morning commute should expect delays on the M1 Princes Motorway near Cataract.
A B-Double truck broke down about 4.30am and both northbound lanes are closed. Vehicles are able to pass slowly using the road shoulder.
There have also been multiple accidents in the heavy traffic queue.
Traffic is banked up for about a kilometre. Roads and Maritime Services and emergency services are on the scene.
Motorists are advised to use Bulli Pass, allow extra travel time and use caution.